Generally speaking, there are three popular types of concrete finishes: exposed aggregate concrete, broom-swept concrete, and trowel finished concrete.
Concrete primarily comprises sand, cement, and aggregate. Exposed aggregate is a concrete finish wherein the top layer of concrete is washed off before it dries to expose the aggregate. Typically, the aggregate used in concrete construction is pea gravel.
A broom swept concrete finish is troweled, but while still wet the concrete is swept with a broom to provide a textured surface. This texture primarily provides slip resistance when the surface is wet. It is commonly used for sidewalks, some parking lots, and driveways. It is typically lighter in color than concrete that is troweled smooth.
Trowel finished concrete is concrete that is smoothed with a trowel upon being poured. A trowel is a flat-bladed hand tool for leveling, spreading, or shaping substances such as cement. Trowel finished smooth concrete is typically used for garage, warehouse, and other indoor floors. With respect to the exposed aggregate concrete, typically the top ⅛-¼″ of the concrete is washed away after the initial pouring and after the concrete is troweled.
Several prior products with respect to concrete repair have been offered. Typically, the existing concrete crack fillers are gray in color and smooth in texture. The commercial concrete crack fillers are typically colored to match the color of a trowel finished concrete surface. Additionally, commercial crack fillers are typically smooth in texture to match the smooth surface of a trowel finish concrete surface.
German Patent No. DE 3617966 discloses a process for producing joint ceiling strips used in exposed aggregate parts. The process includes mixing the joint ceiling composition with a color component.
U.S. Pat. No. 4,205,040 discloses an exposed aggregate finishing method for in-situ concrete. In this method, the concrete setting retarder is protected by an organic high polymer that is water resistant, but soluble in an aqueous solution of cement alkaline.
U.S. Pat. No. 4,810,748 discloses a silicone sealer composition that allegedly exhibits excellent bonding characteristics to dolomite-containing concrete (such as a concrete highway). Additionally, this reference discloses that dolomite is used for aggregate in concrete. The sealant composition comprises a silane group, a crosslinking agent, an epoxy group, and a filler. Fillers include calcium carbonate, alumina, and glass microballons, etc. Pigments and dyes may be added to the composition.
U.S. Pat. No. 4,915,888 discloses a method of making a decorative cement block that includes a thin, surface dressing aggregate. A point aggregate of fine grain is sealed in a space between the surface dressing aggregate. The point aggregate may be sand. Further, the point aggregate may be “highly colorful” to harmonize with the dressing aggregate. A mortar or paste may be used to prevent displacement of the point aggregate. The mortar may have an acrylic reinforcing agent.
U.S. Pat. No. 5,634,037 discloses a liquid acrylic solution as a binding agent for cement, sand, and limestone mixture. The mixture is used to create artificial stones.
U.S. Pat. No. 6,016,635 discloses a method for forming a surface-seeded exposed aggregate concrete. The aggregate may include sand. More specifically, this patent is directed to a method of applying an exposed aggregate surface by broadcasting pea gravel on the surface of wet concrete, which is different then that typical method that is discussed above.
As discussed above, there are commercial products comprising latex emulsions that are designed to repair cracks in concrete. However, they are more designed for an all-purpose type repair and aesthetically only come close to matching the texture and appearance of trowel finished concrete.
What is needed, then, is a concrete repair product that blends aesthetically with respect to the texture and color of exposed aggregate concrete or the color and texture of broom-swept concrete.